The present invention relates to an improved bandage, and more particularly, to a bandage containing a polyurethane hydrogel material suitable for absorbing bodily fluids such as wound exudate without adhering to a wound on which the bandage is mounted.
In the art of protecting minor cuts, scratches, abrasions, and similar injuries, particularly on a temporary, self-treatment basis, the use of the so-called self-adhesive bandage has become widespread. Bandages, such as the self-adhesive type, essentially involve a length of adhesive tape with a pad of gauze, or similar material, located in the center portion thereof, the entire length being covered by a separable layer of release paper or liner which preserves the sterility of the gauze, and renders the adhesive properties of the paper inoperative until the paper is removed prior to application of the bandage. Such bandages are commercially available in a variety of shapes and sizes and are both inexpensive and easy to apply, which helps to account for their widespread popularity.
One problem, however, with these bandages is that the gauze portion of the bandage has a tendency to become saturated with wound exudate. As the wound exudate dries, it forms an adherent bond between the bandage and the wound. Accordingly, when an attempt is made to remove the bandage from the wound, the result is not only painful, but in addition, the new cell tissue forming is torn away from the wound, thereby inhibiting the healing process. A further consequence of having a bandage with a gauze pad saturated with wound exudate is that the wound is extremely vulnerable to infection. In an attempt to avoid this problem, the gauze portion of the bandage has been treated with or formed from hydrophobic fibers such as synthetic fibers. Such attempts, however, have not avoided the adherency which has been experienced between the wound and the gauze due, in part, to the tendency of wound and other bodily fluids penetrating around the fibers and into the interior of the gauze. The bodily fluids, including wound exudate, perspiration, etc., tend to solidify, thereby creating the undesired adherence between the bandage and the wound. There have also been attempts to incorporate sheets of hydrophobic materials, as opposed to gauze, adjacent to the wound surface. The surface irregularities of these sheets, however, facilitate formation of the bond between the bandage and the wound and therefore, do not provide a viable alternative.
In yet another attempt to provide an improved bandage of the self-adhesive type, Morgan, U.S. Pat. No. 4,930,500, discloses a self-adhesive bandage which comprises a hydrophilic gel located on a bandage carrier strip. The hydrophilic gel comprises water and a polyol mixed with the reaction product of a bis-crosslinking agent with an acrylamide compound. While such a hydrophilic gel may avoid or minimize the adherence of the bandage with the wound over which it is placed, it does not absorb sufficient quantities of wound exudate and/or other bodily fluids to promote the healing of the wound satisfactorily. Furthermore, the hydrophilic gel material, as disclosed by Morgan, has a tendency to break apart upon absorption of such fluids. Thus, upon removal of the bandage from the wound, the hydrophilic gel material breaks apart leaving fragments and pieces of gel material in the wound such that the healing process of the wound is inhibited. Moreover, the bandage disclosed in Morgan is not made from transparent materials and thus, the wound may not be visually inspected without removing the bandage. As is known, frequent removal and replacement of the bandage tends to inhibit the healing process since new cell tissue is destroyed upon each removal.
Accordingly, there is a need for a bandage of the self-adhesive type which includes a material having the ability to absorb sufficient amounts of wound exudate and other body fluids and satisfactorily promote the healing of the wound yet maintain its structural integrity even upon removal of the bandage from the wound. There is also a need for a bandage which permits visual inspection of the wound without removing the bandage from the wound.